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101 lines
2.5 KiB
Python
101 lines
2.5 KiB
Python
#
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# The Python Imaging Library
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# $Id$
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#
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# FITS stub adapter
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#
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# Copyright (c) 1998-2003 by Fredrik Lundh
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#
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# See the README file for information on usage and redistribution.
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#
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from . import Image, ImageFile
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_handler = None
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def register_handler(handler):
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"""
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Install application-specific FITS image handler.
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:param handler: Handler object.
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"""
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global _handler
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_handler = handler
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# --------------------------------------------------------------------
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# Image adapter
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def _accept(prefix):
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return prefix[:6] == b"SIMPLE"
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class FITSStubImageFile(ImageFile.StubImageFile):
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format = "FITS"
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format_description = "FITS"
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def _open(self):
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offset = self.fp.tell()
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headers = {}
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while True:
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header = self.fp.read(80)
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if not header:
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raise OSError("Truncated FITS file")
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keyword = header[:8].strip()
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if keyword == b"END":
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break
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value = header[8:].strip()
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if value.startswith(b"="):
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value = value[1:].strip()
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if not headers and (not _accept(keyword) or value != b"T"):
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raise SyntaxError("Not a FITS file")
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headers[keyword] = value
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naxis = int(headers[b"NAXIS"])
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if naxis == 0:
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raise ValueError("No image data")
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elif naxis == 1:
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self._size = 1, int(headers[b"NAXIS1"])
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else:
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self._size = int(headers[b"NAXIS1"]), int(headers[b"NAXIS2"])
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number_of_bits = int(headers[b"BITPIX"])
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if number_of_bits == 8:
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self.mode = "L"
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elif number_of_bits == 16:
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self.mode = "I"
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# rawmode = "I;16S"
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elif number_of_bits == 32:
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self.mode = "I"
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elif number_of_bits in (-32, -64):
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self.mode = "F"
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# rawmode = "F" if number_of_bits == -32 else "F;64F"
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self.fp.seek(offset)
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loader = self._load()
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if loader:
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loader.open(self)
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def _load(self):
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return _handler
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def _save(im, fp, filename):
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if _handler is None or not hasattr("_handler", "save"):
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raise OSError("FITS save handler not installed")
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_handler.save(im, fp, filename)
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# --------------------------------------------------------------------
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# Registry
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Image.register_open(FITSStubImageFile.format, FITSStubImageFile, _accept)
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Image.register_save(FITSStubImageFile.format, _save)
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Image.register_extensions(FITSStubImageFile.format, [".fit", ".fits"])
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